The present invention relates to a device for compensation of voltage drop at light sources of vehicles having an electrical auxiliary charging device, wherein the auxiliary charging device is comprised of an electric motor and a compressor. The electric motor is supplied with electricity by the vehicle battery, and the light sources and the auxiliary charging device are connected in parallel.
From German patent application 44 99 650 it is known to provide, in addition to the exhaust gas turbo charger, an electrically operated charger which is arranged upstream of the exhaust gas turbo charger and which is activated only in the phase of running up the internal combustion engine in order overcome the so-called turbocharger lag. The electric motor of the charger is supplied with electrical energy by the vehicle battery. Once the exhaust gas turbocharger provides enough charging air, the electric charger can be switched off and bypassed by a switch valve. A disadvantage of such a device is the great voltage drop at the terminals of the vehicle battery when the electric motor is switch on. During operation of such a device, the light output of light sources of the vehicles will show a distinct drop caused by the voltage drop since the light sources are also supplied by the vehicle battery. The light sources in question are, for example, the exterior lights and the passenger compartment lights.
It is therefore an object of the present invention to provide a means for maintaining at a constant level the light output of light sources of a vehicle, especially such light sources which are provided to increase vehicle safety.